Azithromycin

Class: Macrolide Antibiotic (Azalide subclass)

Mechanism: Inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing translocation.

Dosage

• Children: 10 mg/kg on Day 1, then 5 mg/kg once daily on Days 2–5
• Adults: 500 mg on Day 1, then 250 mg once daily on Days 2–5

Maximum Dose

500 mg/day (oral or IV)

Side Effects

• GI upset (nausea, vomiting, diarrhea, abdominal pain)
• QT prolongation, arrhythmias
• Headache, dizziness
• Hepatotoxicity (rare)
• Allergic reactions (rash, anaphylaxis — rare)

Contraindications

• Hypersensitivity to azithromycin, erythromycin, or other macrolides
• History of cholestatic jaundice or hepatic dysfunction with azithromycin
• Caution in patients with known QT prolongation or arrhythmias

Compatible Solvent

• Oral suspension: Reconstitute with sterile water
• IV infusion: Dilute with 0.9% NaCl or 5% Dextrose

Route of Administration

• Oral (tablet, suspension)
• Intravenous infusion (not IV push)

Special Precautions

• Use with caution in hepatic impairment
• Adjust dose in severe renal impairment (CrCl < 10 mL/min)
• Monitor ECG if risk factors for QT prolongation present
• Fewer CYP3A4 interactions compared to clarithromycin/erythromycin